5 Plank Mistakes That Make the Move Ineffective (and Potentially Painful)

We all have that one friend who can allegedly hold a plank for 15 minutes. While none of us have ever stuck around long enough to actually ‌see‌ this astounding, 15-minute plank, it's pretty safe to assume that the form probably isn't perfect, especially toward the end of the time cap.

Whether you're holding a super-long plank or practicing the move for 30 seconds at a time, the exercise becomes pointless if you're not doing it properly. Brush up on the correct plank form and absolutely avoid these five common mistakes.

One of the most common plank mistakes is arching the lower back, says April Whitney, CSCS. As your core starts to fatigue, it's common to let your midsection sag toward the ground, causing your back to fall out of alignment.

Although this error doesn't always cause immediate injury, this mistake causes stress on the lower back, which, over time, leads to lower back pain or sensitivity, Whitney says.

Letting the lower back arch also takes the core-strengthening benefits out of the exercise. That's because your abdominals are no longer working to hold your body up, ultimately stalling your progress.

Looking up at a mirror or clock during your plank may help you check your form or stay on track, but it can also wreak havoc on your form, Whitney says. The key to a plank lies in keeping your entire body in a straight line from head to hips to heels.

Glancing at a clock or mirror on the wall will throw your body out of alignment. And holding your head in this position for even a few planks a week can cause soreness in your neck and tightness in the upper back muscles, Whitney says.

About 45 seconds into a minute-long plank, you may be tempted to hike the hips to the ceiling or sag them toward the ground to give your abs a break. You may even be doing it without realizing it!

"Hiking the hips up to the ceiling is going to take the emphasis off your core and load it more onto your shoulders, making it a different exercise," Whitney says. "To get the most out of a plank for your core, you'll want to keep your hips in a straight line with your body, with the pelvis tucked under."

As your plank holds get longer and your body begins to shake (hang in, you're almost there!), you may notice your breath grow uneven. This is the perfect time for a form check — are you shoulders hunched up around your ears?

If the answer is yes, you're making another plank mistake. Bunching the shoulders up can make your upper back muscles tight and cause your neck to strain against the tension, Whitney says. Plus, bunched up shoulders makes it more difficult to maintain an even breathing pattern, which is necessary for any exercise.

It's no surprise plank challenges are a thing on social media. Most of them require you to stay off the ground in a plank for longer and longer increments week after week. But when it comes to proper plank practice, that philosophy totally misses the mark, according to the American Council on Exercise (ACE).

Holding a plank for minutes on end inevitably leads to fatigue and is sure to cause a breakdown of form. And performing any exercise with bad form is pointless. ‌If‌ you can actually hold a plank for several minutes at a time with good form, the exercise is probably too easy for you.